Not quite ready to make my full blown observations yet, but, it certainly is a quiet little amp. I have the new Mullards in it and those tubes seem to like particular speakers. Course I am waiting for rabbit to get back so we can finish adding the little resisters & diodes so that may change things. The Mullards do have a little distortion in the bass the Sovtek's didn't have. Course the Sovteks like going nuclear on a whim so they are out. I have my little cannon fodder Boston Acoustics that were unplayable with these amps. The bass distorted really bad. My Khorns don't distort but the bass sounds crappy. My Lowthers seem to love these amps and a pair of Snell K types as well.